This song has a classy love-song feel, but the lyrics are fairly explicit. The song seems to be about the difference between sex for enjoyment versus procreation.
The lyrics initially brought accusations of sexism upon the band, but it's clear from the second verse that singer Joe Strummer is in fact parodying reggae songs with sexual lyrics, pretending to write from the perspective of a Jamaican man who mocks:
You Western man, you're free with your seed When you make lovers rock But woops! there goes the strength that you need To make real cool lovers rock
"Lovers Rock" uses a kind of UK reggae music popularized by artists like Maxi Priest and Aswad with explicitly sexual lyrics. Many thought The Clash were actually celebrating the genre with the present song, but it's fairly safe to assume that the band were actually parodying the genre - notice in the outro Strummer muttering "ridiculous, innit?"
Bitcoin Bicyclist from OccidentalSeems to me that it could be partially inspired by Mantak Chia who writes in books like Taoist Secrets of Love about how frequent ejaculations lead to dissipation of strength.
Eddie Vedder often changes the words when he sings "Yellow Ledbetter." The basic story is about a guy whose brother dies in the first Gulf War. Apparently, bad news in the army is given in yellow envelopes.